1. Field of the Invention
The present invention relates generally to a protective device, and particularly to a cover for a heat sink to protect thermal interface material spread on the heat sink from contamination before the heat sink is assembled to a CPU or CPU module.
2. Description of Related Art
Electronic devices such as central processing units (CPUs) generate a lot of heat during normal operation. If the heat generated by the electronic devices is not properly dissipated, it can deteriorate their operational stability and damage associated electronic devices. Thus the heat must be quickly and efficiently removed to ensure the normal operation of these electronic devices. As shown in FIG. 5, a heat dissipation device 95a is used to be attached onto a top surface of a CPU (not shown) to remove heat therefrom. Thermal interface material 93a, such as thermal grease, is spread on a bottom of the heat dissipation device 95a. The thermal interface material 93a is used to fill gaps between the heat dissipation device 95a and the CPU. The thermal interface material 93a is used to ensure that the heat dissipation device 95a has an intimate contact with the CPU. A grease cover 90a is attached to the bottom of the heat dissipation device 95a to cover the thermal interface material 93a. Accordingly, during transportation, dust will not contaminate the thermal interface material 93a. However, air channels 952a which are formed between fins 950a of the heat dissipation device 95a still communicate the bottom of the heat dissipation device 95a with ambient air around the heat dissipation device 95a. Accordingly the thermal interface material 93a is easily to be contaminated by dust or foreign particles through the air channels 952a; when this happens, heat transfer performance of the thermal interface material 93a is deteriorated.
What is needed, therefore, is a protective device which can totally prevent dust or foreign particles from contaminating thermal interface material spread on a heat dissipation device.